Sockets for testing integrated circuit devices typically include a clamp for holding the integrated circuit device and a frame for pressing the device against contacts which match with pins of the integrated circuit device. FIG. 1 shows a prior art socket for holding an integrated circuit device to be tested. Such sockets are widely used in the integrated circuit manufacturing industry. Socket 100 comprises lid 101 and base 111 which are rotatably attached through hinge 105. An integrated circuit to be tested, 150 is inserted with the aid of alignment posts 107 onto contacts 109. Lid 101 is then lowered such that clamp 103 comes against the upper surface of integrated circuit device 150 so that clamp edges 103a come against pins 153 of integrated circuit device 150, pressing pins 153 firmly against contacts 109. This arrangement works successfully for newly manufactured integrated circuits in which all pins 153 are aligned with respect to each other and therefore seat correctly against contacts 109 when lid 101 is lowered.
A problem arises when using the structure of FIG. 1 for testing integrated circuit devices which have been attached to a printed circuit board and then removed because of an apparent defect. The attachment and removal process with consequent soldering and unsoldering of pins 153 typically results in pins 153 becoming misaligned with respect to each other and with respect to contacts 109. When a used device is reinserted into a socket such as socket 100, the pins may fail to contact their corresponding ones of contacts 109. A pin may contact more than a single contact 109 and thereby short adjacent contacts, or may even be lifted by solder remaining on some of pins 153 such that other of pins 153 may fail to contact their corresponding ones of contacts 109.
For PLCC packages, commercial pin-straigteners are available. Further, for PLCC packages, test sockets contact the sides of the pins close to where they leave the package, so the sockets are less sensitive to pin distortion. However, for PQFP and CQFP packages, which can have a finer pin pitch, no pin straighteners are available. These are very delicate packages. The chips must be inserted into the socket with a vacuum device for holding the chip in the proper orientation, and dropping it precisely into its position in the socket. When the pins are misaligned, it has usually not been possible to test these devices.